Slow download speed despite strong 4G or 5G signal

[h2005]

Hi

In some areas I find that even though my phone has a medium/strong 4G or 5G connection, the internet is virtually unusable as the download speeds are less than 1Mb. There doesn't seem to be a pattern, though some areas seem more prone than others.

For example it's OK most of the time where I live in Essex, but last year I was staying in a part of Devon where it was continually slow despite showing a strong signal (and virtually unusable), yet the speed would recover just a mile or two away. I tried my work phone (on O2) and that also had the same issue.

At the moment I'm in Wales where signal's been notoriously bad in the past, but now there's very good 4G/5G coverage, but again the speed can vary from full 4/5G speed down to 1 or 2Mb. 

Is there any reason for this happening and anything I can do? I sometimes find putting my phone into aeroplane mode and out again can help - not sure if that's a coincidence or not (and it doesn't always solve it). The time of day doesn't seem to matter either.

Thanks.

[bristolian]

Data speeds do not directly correlate to the displayed signal strength, but the available capacity on the serving site/sector - in turn this is dictated by "spectrum available divided by users". Comparing with another network is intriguing, but no use beyond that.

Equally, the single 4G or 5G "signal" you see is made up of multiple different frequency layers - each with different characteristics. Very broadly, high-band frequencies provide better capacity but with lesser coverage. Low-band frequencies improve the coverage, but with more limited capacity for heavy use - a good network deployment has a combination of both.

Can you be more specific about where in Wales and/or Devon you had issues?

[h2005]

Thanks, that's interesting. The issues I had in Wales were/are in the Barmouth and Porthmadog areas (only sporadic issues), while in Devon it was around Exmouth (continual issues).

[bristolian]

EE's base coverage layer is 4G on Band3-1800Mhz (mid-band), with Band20-800Mhz used as an "extended range" layer in rural areas. Band1-2100Mhz & Band7-2600Mhz are mainly found in dense coverage areas.

Barmouth & Porthmadog areas both have a good B3 & B20 presence, and I've found it generally performs well around Snowdonia. Exmouth has service from all bands. Not every site has every band, there are common configs but it's not universal.

[h2005]

Thanks for info.

Is there any reason why the speed fluctuates so much in certain areas and at random times of day? Sometimes going in and out of aeroplane mode can help - does that cause something to change?

[bristolian]

Flight mode is just a disconnect/reconnect - it can be useful where particular network services simply aren't working, by means of break/make theory. In this case, the amount of capacity available isn't changing so the effect may be perception or short-term by reconnecting to another carrier for a short time before radio conditions are deemed too poor.

Significant speed fluctuations would tend to suggest a wide variation in traffic levels - perhaps an influx of users, increase in usage or a site/sector/carrier being out-of-service.

[h2005]

The flight mode switch can definitely help - sometimes if the speed drops to 1Mb or even less, it goes back up to 20+Mb after switching flight mode on and off. Sometimes forcing 4G (rather than letting it automatically connect to 5G) can also have a similar effect.

I assume my Devon experience where my O2 work phone was also struggling was due to a fault somewhere locally.

[bristolian]

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@h2005 wrote:

I assume my Devon experience where my O2 work phone was also struggling was due to a fault somewhere locally.

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Maybe, maybe not. O2 has a fundamentally different radio design to EE. They are primarily a low-band network with 800Mhz &/or 900Mhz service available on all sites, but without an equally universal deployment of mid & high-band that provide additional capacity.

There's various national benchmarking surveys that rank each of the big-4 networks against multiple criteria. O2 have consistently performed poorly for data speeds over recent years.

Having a 5G device in your case, adds additional variables. EE have 4G service on every UK site, not so 5G. So if your closest site has, say, high-cap 4G carriers but only single 5G ones - your phone will prefer the 5G by design. Or if 5G service is coming from a more distant site, you can get lower on-screen bars by using that preferred 5G, when 4G may be available from a closer site.

Edited to add that I am oversimplifying some of the detail here,  but it's to help give an idea.

[h2005]

It's happened a few times this evening where I'm staying (nr. Porthmadog), where the speed drops slowly to become unusable, then when I do the aeroplane mode off/on it recovers back to a pretty decent speed.

I think your comment earlier about what the aeroplane mode is doing hits the nail on the head: "....by reconnecting to another carrier for a short time before radio conditions are deemed too poor."

When you refer to another carrier, do you mean another mast? Is there any way to force switching to another carrier before the speed drops too low? This would then avoid having to do the aeroplane mode trick.

Thanks.

[bristolian]

My reference to carrier is, loosely, to individual frequencies on a particular site. Depending on config, you can have 1 x 800Mhz carrier, upto 2 x 1800Mhz, 1 x 2100Mhz, 3 x 2600Mhz (I'm keeping this purely 4G for simplicity)

Say you're on the edge of 1800Mhz with good 800Mhz - the phone will prefer 1800Mhz where usable, but will fallback to 800Mhz when not. Reverting to 1800Mhz once conditions improve.

1800Mhz, 2100Mhz & 2600Mhz are all equally weighted.